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  • 1965-1969  (3)
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  • 1
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 220 (1968), S. 940-940 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] SIR,-The McCarthy Report recognizes from the outset that attempts to predict the absolute number of scientists and technologists required by the British economy are most likely to be unsuccessful and concentrates instead on attempting to predict the relative proportion of specialist scientists to ...
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1617-4623
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary It has been shown in Drosophila melanogaster that when 50 or fewer sperm are stored in the female, some 58% are found in the spermathecae and 42% in the ventral receptacle. When between 51 and 100 are stored, some 34% are found in the spermathecae and 66% in the ventral receptacle. The more commonly encountered distribution of 10–20% in the spermathecae and 80–90% in the ventral receptacle hold for higher levels of insemination (greater than 100 sperm). The reason for the relatively high proportion of sperm stored in the spermathecae when the total number of sperm stored is small is unknown. It is pointed out that in experiments dealing with sperm: progeny ratios, careful counting of sperm in the spermathecae becomes of critical importance, especially at low levels of insemination.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1617-4623
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Experiments were carried out to determine the number of sperm transferred by the maleDrosophila after X-irradiation. Acute doses (1000 r/min) of 5,000 r, 25,000 r and 50,000 r delivered to the male results in reductions of some 20–25%, 60–65%, and 85–90%, respectively, in the number of sperm scored in the ventral receptable of inseminated females. It appears, further, that sperm in ejaculates of relatively small size (50 or fewer) from irradiated as well as unirradiated males distribute themselves such that 20–50% or more found in the spermathecae. The bearing of this observation on the apparent 1:1 sperm: progeny ratio reported byPeacock andErickson (1965) from ejaculates with low sperm number is noted.
    Type of Medium: Electronic Resource
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